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Test Code
This is the recommended study for diagnosis of gestational diabetes in pregnant patients.
Container TypeSerum separator tube (gold, brick, SST, or corvac)
Supply Item Numberpicture1467
Specimen TypeSerum
Preferred Volume2 mL each specimen
Minimum Volume0.3 mL each specimen
Patient PrepThis test should be done in the morning after an overnight fast of between 8 and 14 hours, and after at least 3 days of unrestricted diet (150 or more grams carbohydrate per day) and unlimited physical activity. The patient should remain seated and should not smoke throughout the test. Patient can have nothing by mouth except water during test period. GLUCOSE DOSE: 100 grams.
Collection ProcedureDraw fasting specimen just prior to 100 gram glucose load. Draw 1 hour, 2 hour and 3 hour post-dose specimens. Clearly label specimens.
Specimen ProcessingSeparate serum from cells within 30 minutes of collection and transfer to standard PAML aliquot tube.
Store and TransportRefrigerated
StabilityRefrigerated 2 weeks if separated from the cells within 30 minutes of collection  
Alternate SpecimensLithium heparin or sodium fluoride/potassium oxalate (green or gray top tube). Gray top tube whole blood is stable 24 hours.
CPT Codes82951, 82952
Billing CodeGTPG
Test ScheduleSun-Fri nights
Turnaround Time1-2 days
Test IncludesGlucose-Preg, fasting, mg/dL; Glucose-Preg, 1 hour, mg/dL; Glucose-Preg, 2 hour, mg/dL; Glucose-Preg, 3 hour, mg/dL
Reference Ranges
Glucose, Pregnant
 Two or more of the following threshold
 values must be met or exceeded to
 confirm gestational diabetes:
  Fasting     95    mg/dL
  1 hour      180    mg/dL
  2 hour      155    mg/dL
  3 hour      140    mg/dL
These criteria apply to the 3-hour (100 gram) ACOG glucose tolerance testing protocol for gestational diabetes.
NotesCall PAML for printed diet instructions

Interface Codes
typeorder codetest descriptionresult coderesult descriptionunitsdecimal placesloinc code
o84999.Z77Glucose Tolerance, Pregnancy 3 hr
r84999.Z77Glucose Tolerance, Pregnancy 3 hr82951.Z4Glucose, Fastingmg/dL01558-6
r84999.Z77Glucose Tolerance, Pregnancy 3 hr82951.Z5Glucose, 1 hrmg/dL020438-8
r84999.Z77Glucose Tolerance, Pregnancy 3 hr82951.Z6Glucose, 2 hrmg/dL020436-2
r84999.Z77Glucose Tolerance, Pregnancy 3 hr82952.Z6Glucose, 3 hrmg/dL020437-0